Remapped Packaged Extracted Die

ABSTRACT

A remapped extracted die is provided. The remapped extracted die includes an extracted die removed from a previous integrated circuit package. The extracted die includes a plurality of original bond pads having locations that do not correspond to desired pin assignments of a new package base and an interposer, bonded to the extracted die. The interposer includes first bond pads configured to receive new bond wires from the plurality of original bond pads, and second bond pads corresponding to desired pin assignments of the new package base, each individually electrically coupled to one of the first bond pads and configured to receive new bond wires from package leads or downbonds of the new package base.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a Continuation-in-Part of pending U.S. applicationSer. No. 13/623,603 (Docket No. GCP0002 US), filed Sep. 20, 2012,entitled ENVIRONMENTAL HARDENING TO EXTEND OPERATING LIFETIMES OFINTEGRATED CIRCUITS AT ELEVATED TEMPERATURES, which is herebyincorporated by reference for all purposes, which is a Continuation ofU.S. application Ser. No. 13/283,293 (Docket No. GCP0001 US) filed Oct.27, 2011, entitled ENVIRONMENTAL HARDENING TO EXTEND OPERATING LIFETIMESOF INTEGRATED CIRCUITS AT ELEVATED TEMPERATURES, now abandoned.

FIELD

The present invention is directed to integrated circuit packaging. Inparticular, the present invention is directed to methods and apparatusesfor utilizing extracted dice in new packaged integrated circuits.

BACKGROUND

Integrated circuits are available in many different packages,technologies, and sizes. Most integrated circuits are available inplastic packages, which are generally intended for commercial operatingenvironments at a low cost. Commercial operating environments have aspecified operating range from 0° C. to 70° C. Integrated circuits formilitary applications have historically been packaged in either metal orceramic hermetic packages, which are able to work reliably in moredemanding environments than commercial integrated circuits. Militaryoperating environments have a specified operating range from −55° C. to125° C. In order to save costs, the military has purchased integratedcircuits through COTS (Commercial Off-The-Shelf) programs. However,these components are generally commercial grade components in plasticpackages, and not intended for demanding environments requiring thebroader temperature range reliability and durability of ceramic andmetal hermetically packaged integrated circuits.

Depending on size and complexity, integrated circuits are available in awide range of packages. Although many older integrated circuits werepackaged using through-hole technology packages, surface mount packageshave dominated over the past several decades. Surface mount packagesgenerally have circuit density, cost, and other advantages overthrough-hole integrated circuits. Examples of through-hole packagesinclude DIP (dual-in-line plastic) and PGA (pin grid array). Examples ofsurface mount packages include SOIC (small-outline integrated circuit)and PLCC (plastic leaded chip carrier).

Integrated circuit packages generally consist of a semiconductor dieplaced within a package base and bonded to the base with a suitable dieattach adhesive. In conventional technology, the die is electricallyattached to a lead frame of the package base with discrete bond wires,which connect individual pads of the die with package leads. In mostcases, the bond wires are gold, but in other environments can be copperor aluminum. Specialized equipment is required to attach the bond wiresto the die pads the lead frame. Once all of the bond wires are attached,the package lid is bonded to the package base and the integrated circuitcan be tested.

SUMMARY

The present invention is directed to solving disadvantages of the priorart. In accordance with embodiments of the present invention, a remappedextracted die is provided. The remapped extracted die includes anextracted die which includes a plurality of original bond pads havinglocations that do not correspond to desired pin assignments of a newpackage base and extracted from a previous integrated circuit package,and an interposer, bonded to the extracted die. The interposer includesfirst bond pads configured to receive new bond wires from the pluralityof original bond pads, and second bond pads corresponding to desired pinassignments of the new package base, each individually electricallycoupled to one of the first bond pads and configured to receive new bondwires from package leads or downbonds of the new package base.

In accordance with another embodiment of the present invention, apackaged integrated circuit is provided. The packaged integrated circuitincludes an extracted die removed from a previous packaged integratedcircuit, and a new package base. The new package base includes packageleads. The packaged integrated circuit also includes an interposer,bonded to the extracted die and the new package base. The interposerincludes first and second bond pads. The packaged integrated circuitfurther includes new bond wires, provided between the extracted die andfirst bond pads and between the second bond pads and package leads ordownbonds to the new package base, and a package lid sealed to the newpackage base.

In accordance with a further embodiment of the present invention, a newhermetic packaged integrated circuit is provided. The new hermeticpackaged integrated circuit includes a new hermetic package base,including a cavity and package leads, and a remapped extracted die,secured within the cavity. The remapped extracted die includes anextracted die removed from a previous packaged integrated circuit and aninterposer, bonded to the extracted die and the new hermetic packagebase. The extracted die includes no original ball bonds or bond wirespresent on original bond pads, no residues or oxides present on originalbond pads, and one or more reconditioned bond pads. Each of the one ormore reconditioned bond pads includes a nickel layer covering anoriginal bond pad, a palladium layer covering the nickel layer, and agold layer covering the palladium layer. The interposer includes firstbond pads electrically coupled to second bond pads. The new hermeticpackaged integrated circuit also includes new bond wires, bonded betweenthe reconditioned bond pads and the first bond pads and between thesecond bond pads and the package leads or downbonds, and a package lidsealed to the new hermetic package base.

An advantage of the present invention is that it allows a packagedintegrated circuit to be produced even if the die or wafers needed areout of production. Sometimes, the only way to obtain new packagedintegrated circuits is to reuse extracted dice from previous packagedintegrated circuits.

Another advantage of the present invention is it provides a way torepackage an extracted die for a different package and pinout than theextracted die was originally packaged for. There is no limit to thepinouts that may be thusly created, and by using different interposers,extracted dice may be utilized in many different packages and pinouts.

Additional features and advantages of embodiments of the presentinvention will become more readily apparent from the followingdescription, particularly when taken together with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an extracted die with original bondpads, original ball bonds, and original bond wires in accordance withembodiments of the present invention.

FIG. 2A is an illustration depicting a section A-A of an extracted diein accordance with embodiments of the present invention.

FIG. 2B is an illustration depicting a section A-A of a modifiedextracted die after original ball bond removal in accordance withembodiments of the present invention.

FIG. 2C is an illustration depicting a section A-A of an extracted diewith electroless Nickel layer application in accordance with embodimentsof the present invention.

FIG. 2D is an illustration depicting a section A-A of an extracted diewith an electroless Palladium layer in accordance with embodiments ofthe present invention.

FIG. 2E is an illustration depicting a section A-A of an extracted diewith an immersion Gold layer in accordance with embodiments of thepresent invention.

FIG. 2F is an illustration depicting a section A-A of an extracted diewith new bond wires and new ball bonds in accordance with embodiments ofthe present invention.

FIG. 3A is an illustration depicting a section A-A of an extracted dieafter a first rebonding process in accordance with embodiments of thepresent invention.

FIG. 3B is an illustration depicting a section A-A of an extracted dieafter a second rebonding process in accordance with embodiments of thepresent invention.

FIG. 4A is an illustration depicting an assembled new package base withnew bond wires in accordance with embodiments of the present invention.

FIG. 4B is an illustration depicting an assembled non-hermeticintegrated circuit package with an extracted die in accordance withembodiments of the present invention.

FIG. 4C is an illustration depicting an assembled hermetic integratedcircuit package with an extracted die in accordance with embodiments ofthe present invention.

FIG. 5 is an illustration depicting an interposer for an extracted diein accordance with embodiments of the present invention.

FIG. 6A is an illustration depicting a top view of a new package basebefore wire bonding in accordance with embodiments of the presentinvention.

FIG. 6B is an illustration depicting a top view of a new package baseafter wire bonding in accordance with embodiments of the presentinvention.

FIG. 7A is a flowchart illustrating an assembly method for a packagedintegrated circuit in accordance with a first embodiment of the presentinvention.

FIG. 7B is a flowchart illustrating an assembly method for a packagedintegrated circuit in accordance with a second embodiment of the presentinvention.

FIG. 8A is a flowchart illustrating an assembly method for a hermeticpackaged integrated circuit in accordance with a third embodiment of thepresent invention.

FIG. 8B is a flowchart illustrating an assembly method for a hermeticpackaged integrated circuit in accordance with a fourth embodiment ofthe present invention.

DETAILED DESCRIPTION

Integrated circuits are most commonly packaged in plastic packages usingdice with Aluminum (Al) bond pads and Gold (Au) bond wires from the bondpads to the package leads and package cavity. Bond wires are attached tobond pads and package leads using thermosonic bonding, wedge bonding, orother processes well understood in the art.

In some cases, bare dice and wafers are generally not available. It istherefore highly desirable to obtain dice from previously packagedintegrated circuits. Integrated circuit dice are then extracted from anexisting package—usually plastic—and repackaged into a suitable packageaccording to the component needs of the market. These extracted diceretain the original Au ball bonds on the Al die pads. In some cases,extracted dice are repackaged into commercial plastic packages. In othercases, often military or environmentally hardened applications,extracted dice are repackaged into hermetic ceramic or metal packages.

The present invention is directed to integrated circuits and methods forremoving extracted dice from a previous package and repackaging into adifferent package, generally with a different pinout from the previouspackage.

Referring now to FIG. 1, an extracted die 100 with original bond pads104, 108, original ball bonds 112, and original bond wires 116 inaccordance with embodiments of the present invention is shown. Extracteddie 100 is an individual semiconductor die or substrate, and is usuallyfabricated in suitable technologies including Silicon (Si) and GalliumArsenide (GaAs). Extracted die 100 may have a single die or multipleinterconnected dice. Regardless whether extracted die 100 includes asingle die or multiple interconnected dice, die circuitry is connectedto original bond pads 104, 108 of the extracted die 100. Original bondpads 104, 108 are most commonly aluminum (Al) or copper (Cu) alloy pads,although the present invention is not limited to any particular bond pad104, 108, 504, 508 or bond wire 116, 240 metallurgy.

Each previously used original bond pad 104 of the extracted die 100 mayhave an original ball bond 112 present, although one or more unbondedbond pads 108 may not have an original ball bond 112 present. In somecases, this is due to a no-connect in the previous integrated circuitpackage. When the extracted die 100 was present in whatever previousintegrated circuit package was used for the extracted die 100, originalbond wires 116 connected each of the original ball bonds 112 to a leador a downbond of the previous integrated circuit package. FIG. 1illustrates an exemplary extracted die 100 after it has been removedfrom the previous integrated circuit package. Therefore, some originalbond wires 116 have been removed and some original bond wires 116remain. In current technology packaged integrated circuits, the vastmajority of bond wire interconnections are made with Gold (Au)thermosonic ball bonding. Extracted dice 100 are in the state shown inFIG. 1 at the beginning of the process of the present invention. SectionA-A is used in FIGS. 2A-2F and 3A, 3B to illustrate a side view ofextracted die 100.

Referring now to FIG. 2A, a diagram illustrating a section A-A of anextracted die 100 in accordance with embodiments of the presentinvention is shown. In order to show the assembly of the preferredembodiment of the present invention, a side view of the extracted die100 is provided.

Extracted die 100 includes a die substrate 204 including variousmetallization layers known in the art. On the surface of the diesubstrate 204 are one or more original bond pads 104, 108. A passivationlayer 208 is applied over the die substrate 204 in order to protect thecircuits of the die substrate 204, and the passivation layer 208 isrelieved at each of the original bond pads 104, 108 in order to providebonding access.

Where original ball bonds 112 and original bond wires 116 are applied tooriginal bond pads 104, 108, the original bond pads are original bondpads 104. Where no original ball bonds 112 and original bond wires 116are applied to original bond pads 104, 108, the original bond pads areoriginal bond pads 108. FIG. 2A illustrates the point at which theextracted die 100 has been removed from its' original package and one ormore original ball bonds 112 and original bond wires 116 are present.

Referring now to FIG. 2B, a diagram illustrating a section A-A of amodified extracted die 212 after original ball bond 112 and originalbond wire 116 removal in accordance with embodiments of the presentinvention is shown. A modified extracted die is an extracted die 100with the original ball bonds 108 and original bond wires 116 removed.Although in some embodiments original gold ball bonds 112 may be removedby mechanical means, in most cases it is preferable to use chemicalremoval means by known processes. FIG. 2B illustrates the original ballbond 112 and original bond wire 116 removed from the original bond pad104. Not shown in FIG. 2B is that after removing the original ball bond112 and original bond wire 116, some amount of intermetallic residueand/or oxides will be present on the original bond pads 104. Thisgenerally requires removal to make sure there are no impurities,residues, or oxides on the original bond pads 104, 108. Removal ispreferably performed using a mild acid wash. The acid wash is followedby an acid rinse that removes surface oxides present on the originalbond pads 104, 108. For plating on an Aluminum surface, a zincateprocess is used to etch away a very fine layer of Aluminum from theoriginal bond pads 104, 108 and redeposit a layer of Zinc (Zn) on theoriginal bond pads 104, 108. The fine layer of Zinc will then act as acatalyst for the Nickel plating to follow. Once residues and oxides havebeen removed from the original bond pads 104, 108, in some embodimentsthe surface of the original bond pads 104, 108 is rendered to anincreased degree of flatness by applying a lapping process. This has theadded benefit of providing a uniformly smooth and consistent bond pad104, 108 surface in preparation for followingreconditioning/metallization (ENEPIG—electroless Nickel, electrolessPalladium, immersion Gold, for example) or ball bonding operations. Thevarious such processing steps described above, including removingoriginal ball bonds and bond wires, impurities, residues, and oxides,various acid washes and rinses, and possibly lapping the surface, resultin conditioned original bond pads 244.

Once in a clean and flat state, the conditioned original bond pads 244or original bond pads 108 are ready to be reconditioned. Reconditioningof the present invention is a process whereby the original bond pads 108or conditioned original bond pads 244 are built up by successive andordered application of specific metallic layers prior to new wirebonding processes.

In one embodiment, after an extracted die 100 is removed from a packagedintegrated circuit, only original bond wires 116 are removed—thusleaving original ball bonds 112 on less than all original bond pads 104of the extracted die 100. Original ball bonds 112 must be removed priorto conditioning or reconditioning bond pads. Therefore, in someembodiments the metallic layers of the present invention are providednot to bare original bond pads 108, but rather original bond pads 104following original ball bond 112 removal, or to any original bond pad104, 108 intended to receive a new ball bond 236 and new bond wire 240.Conditioned original bond pads are original bond pads with original bondwires 116, original ball bonds 112, and residue/oxides removed.Reconditioned bond pads are conditioned original bond pads followingapplication of the metallic layer structure shown and described withrespect to FIGS. 2C-2E herein.

Referring now to FIG. 2C, a diagram illustrating a section A-A ofelectroless Nickel layer 216 application in accordance with embodimentsof the present invention is shown. Electroless plating is more costeffective than electroplating since it does not require expensivephotolithography and etch processes. However, electroless processesgenerally require thicker metal layers for good bondability.

A Nickel (Ni) layer 216 applied over conditioned original bond pads hasbeen found to protect pad surfaces. Nickel possesses a much higherelastic modulus than either Copper (Cu) or Aluminum (Al), which leadsNickel to have high stiffness and fracture toughness and resistdeflection and absorb energy during ball bonding processes. Thus, Nickelis a preferred metallic layer 216 for the initial layer applicationfollowing original bond pad 104, 108 conditioning processes.

An electroless Nickel plating bath is very complex and contains morechemicals (i.e. reducing agents, complexant or chelating agents,stabilizers, etc) than the Nickel source alone. These bath componentsare known in the art and perform specific functions during the chemicalreaction. They are important in order to obtain a good quality Nickeldeposit and must be monitored carefully during processing.

The plating rate of Nickel is a controllable parameter during theplating process, which in turn affects the final surface roughness. Afast plating rate will obviously increase the process throughput, butfast plating rates can also result in a rougher Nickel finish.Therefore, a careful balance must be maintained between processing speedand surface quality. If the Nickel surface is too rough, the nextsuccessive metal layers to be plated over the Nickel will follow thecontours and also result in a rougher surface. Both surface hardness androughness have a strong effect on wire bondability and bond strength.Harder and rougher surfaces are typically less bondable. For wirebonding applications, the electroless Nickel layer 216 is generally120-240 microinches thick.

Referring now to FIG. 2D, a diagram illustrating a section A-A ofElectroless Palladium layer 220 application in accordance withembodiments of the present invention is shown. Electroless Palladium(Pd) 220 is applied over the Electroless Nickel (Ni) 216 layer of FIG.2C in order to inhibit Nickel diffusion into the Immersion gold layer224 applied afterward.

Palladium plating was first investigated as a replacement for purelygold plating in order to alleviate the high cost of gold plating.Palladium and Palladium-Nickel alloys were initially developed forcontact wear resistance in connector applications, but other technicaladvantages were identified as usage grew. Not only is a pure Palladiumlayer very hard, but it is also very dense which assists as a diffusionbarrier. As with the Electroless Nickel layer 216, the ElectrolessPalladium layer 220 requires a catalyst pretreatment to prepare thesurface for deposition. The metal source is typically aPalladium-Ammonia compound with a hydrazine reducing agent for metaldeposition. For wire bonding applications, the Electroless Palladiumlayer 220 is generally 2-4 microinches thick, approximately 2 orders ofmagnitude thinner than the Electroless Nickel layer 216.

Referring now to FIG. 2E, a diagram illustrating a section A-A ofimmersion Gold layer 228 application in accordance with embodiments ofthe present invention is shown. The immersion Gold layer 228 is appliedover the electroless Palladium layer 220, and provides the top layer ofthe reconditioned bond pads 232. Gold has long been a mature platingprocess for semiconductor applications. Two types of Gold platingprocesses through chemical reactions are used today: immersion andautocatalytic. Immersion Gold plating 228 is a self-limiting galvanicdisplacement process, where no reducing agent is required. For wirebonding applications, the immersion Gold layer 228 is generally at least1-2 microinches thick, and preferably thicker. Following the processstep of FIG. 2E, the die is a reconditioned die 224.

Because the ENEPIG plating process uses Gold as the wire bonding layerwith Gold bond wire, there is no Aluminum (Al)—Gold (Au) interface thatcan degrade and corrode. Thus, the ENEPIG plating process produces morereliable wire bonding interfaces and is preferred for high temperatureapplications over previous processes that maintained Al—Au interfacesand utilized moisture getter, noble gas insertion, and vacuum bakes topurge moisture from integrated circuit packages.

Referring now to FIG. 2F, a diagram illustrating a section A-A of newbond wires 240 and ball bonds 236 in accordance with embodiments thepresent invention is shown. The combination of the electroless Nickellayer 216, electroless Palladium layer 220, and the immersion Gold layer228 produces a reconditioned bond pads 232. New gold bond wires 240 maybe thermosonically welded to reconditioned bond pads 232, and willproduce a new Gold ball bond 236 at each new bond wire 240 location.

In thermosonic welding, the interface temperature is typically between125° C. and 220° C. For ball bonding, the new bond wire 240 is threadedthrough a capillary-shaped tool, and a spark melts the end of the wireforming a ball at the bottom of the tool. The bond (weld) is formed whenthe tool under load presses or deforms the ball against the heatedbonding pad and ultrasonic energy is applied, completing the process.

Referring now to FIG. 3A, a diagram illustrating a section A-A of anextracted die 100 after a first rebonding process 300 in accordance withembodiments of the present invention is shown. The assembly step shownin FIG. 3A immediately follows the assembly step shown in FIG. 2B, whereall original ball bonds 112 and original bond wires 116 have beenremoved from the extracted die 100, but a bond pad reconditioningprocess such as an ENEPIG process as shown in FIGS. 2C-2F is not used.

Extracted die 100 includes a die substrate 204 including variousmetallization layers known in the art. On the surface of the diesubstrate 204 are one or more original bond pads 104, 108 or conditionedoriginal bond pads 244. A passivation layer 208 is applied over the diesubstrate 204 in order to protect the circuits of the die substrate 204,and the passivation layer 208 is relieved at each of the original bondpads 104, 108 in order to provide bonding access.

Referring now to FIG. 3B, a diagram illustrating a section A-A of anextracted die 100 after a second rebonding process 304 in accordancewith embodiments of the present invention is shown. The assembly stepshown in FIG. 3B immediately follows the assembly step shown in FIG. 2A,where all original bond wires 116 have been removed from the extracteddie 100, but one or more original ball bonds 112 still remain and a bondpad reconditioning process such as an ENEPIG process as shown in FIGS.2C-2F is not used. New ball bonds 236 and new bond wires 240 areprovided either above original ball bonds 112 or original bond pads 108.

Referring now to FIG. 4A, an illustration depicting an assembled packagebase 400 with new bond wires 240 in accordance with embodiments of thepresent invention is shown. The assembled package base 400 includes anew package base 408. In one embodiment, the new package base 408 is anon-hermetic new package base 408. In another embodiment, the newpackage base 408 is a hermetic new package base 408. In non-hermeticapplications, new package base 408 is generally plastic. If the newpackage base 408 is a hermetic package base 408, it may be formed fromceramic, metal, or glass materials.

After conditioning and/or reconditioning any original bond pads 104, 108of the extracted die 100, the extracted die 100 is bonded to aninterposer 404 with a suitable die attach adhesive 412. The extracteddie 100 bonded to the interposer 404 is referred to herein as a remappedextracted die 428. This is described in more detail in FIG. 6A. In oneembodiment, the original bond pads 104, 108 are prepared by removingoriginal bond wires 116. In other embodiments, the original bond pads104, 108 are prepared by removing original ball bonds 112 and originalbond wires 116, and removing any traces of original ball bonds 112,residues, oxides, and other deposits from the original bond pads 104(i.e. conditioning processes as described herein). In some embodiments,the original bond pads 104, 108 are buffed, polished, or lapped beforeadding any new ball bonds 236 and new bond wires 240.

The new package base 408 includes a cavity 416 into which the remappedextracted die 428 is placed. Die attach adhesive 412 is applied to thenew package base 408 such that when the extracted die 100 is insertedinto the new package base cavity 416, the die attach adhesive 412 makessimultaneous contact with both the new package base 408 and theextracted die 100. Although not shown for clarity, a thin layer of dieattach adhesive 412 would bond the extracted die 100 to the interposer404.

In embodiments where the new package base 408 is a component of ahermetic package 452, die attach adhesive 412 is a low-halide compoundadhesive, where a low halide compound has less than 10 parts per million(ppm) halide. Die attach adhesive 412 therefore bonds the extracted die100 to the new package base 408, and protects the integrity of theinterior of the assembled package base 400. It has been well establishedthat halogens in an Au—Al bond interface degrade Au—Al bond strengthsince out-gassed products from adhesives containing halogens rapidlycorrode Al metallization in integrated circuits at high temperatures,thus reducing product lifetime at high temperatures.

Associated with the new package base 408 are a series of package leads424, which provide interconnection between circuitry of the extracteddie 100 and circuitry of a printed circuit board on which the packagedintegrated circuit 440, 452 is eventually mounted. For example, if anS0-24 ceramic package is used for the packaged integrated circuit, 24package leads 424 would be present, configured as 12 package leads 424on each of two opposite sides of the new package base 408. If a PLCC-68ceramic package is used for the integrated circuit, 68 package leads 424would be present, configured as 17 package leads 424 on each of the foursides of the new package base 408. The present invention may be used forany type of previous integrated circuit package or any type of newhermetic 452 or non-hermetic 440 integrated circuit package.

After mounting the remapped extracted die 428 into the new package base408 using a die attach adhesive 412, new bond wires 240 are thenattached as described in more detail in FIG. 6B. New bond wires 240 arecommonly 1-3 mils in diameter, but may be any usable diameter. In oneembodiment, a new ball bond 236 is formed on top of an original ballbond 112. In other embodiments, a new ball bond 236 is formed on top oforiginal bond pads 108. In a preferred embodiment, new bond wires 240are Gold (Au) bond wires. In other embodiments, new bond wires 240 areAluminum (Al) or Copper (Cu) bond wires.

Referring now to FIG. 4B, an illustration depicting an assemblednon-hermetic integrated circuit package 440 with an extracted die 100 inaccordance with embodiments of the present invention is shown. Packagedintegrated circuit 440 is Assembled package base 400 with a package lid432 attached. Where the new package base 408 and package lid 432 arenon-plastic materials, lid seal adhesive 436 is generally required. Innon-hermetic applications, package lid 432 is generally plastic and ismolded to a plastic new package base 408 with an encapsulation process.In such cases, a lid seal adhesive 436 may not be required.

Referring now to FIG. 4C, an illustration depicting an assembledhermetic integrated circuit package 452 with an extracted die 100 inaccordance with embodiments of the present invention is shown. Packagedhermetic integrated circuit 452 includes the assembled hermetic packagebase 400 of FIG. 4A and additional components described below.

For a hermetic integrated circuit package 452 including a hermetic newpackage base 408, once all new bond wires 240 are bonded between packageleads 424 and downbonds and the remapped extracted die 428, theassembled package base 400 including remapped extracted die 428, dieattach adhesive 412, new package base 408, package leads 424, and newbond wires 240, may be first and second vacuum baked according to theprocesses of parent application Ser. No. 13/623,603.

The assembled hermetic integrated circuit package 452 including lowhalide die attach adhesive 412, noble inert gas 448, and moisture getter444 is used for a high-temperature application exposure (greater than150 degrees Celsius) with original bond pads 104 where the original ballbonds 112 were not removed and/or the original bond pads 104, 108 werenot reconditioned 232.

Referring now to FIG. 5, an illustration depicting an interposer 404 foran extracted die 100 in accordance with embodiments of the presentinvention is shown. Interposer 404 is a substrate that the extracted die100 is mounted on one side of, and translates original bond pad 104,108, conditioned original bond pad, or reconditioned bond pad 232locations into bond pad locations that match a desired pinout ofpackaged integrated circuits 440, 452. Interposer 404 is a substrate orother material such as FR-4, Kapton, Teflon, or Polyamide suitable formounting within a new package base 408 and carrying electrical signalsto and from the extracted die 100 and package leads 424 or downbonds.

Interposer 404 includes a location 512 for mounting the extracted die100 or modified die 212 on a specified side of interposer 404. Extracteddie 100 may be secured to interposer 404 with die attach adhesive 412,an epoxy, or other chemical and/or mechanical means known in the art. Inmost embodiments, extracted die 100 is mounted centrally on theinterposer 404 in order to facilitate wire bonding. However, in someembodiments the extracted die 100 may not be centrally mounted oninterposer 404 for various reasons.

Interposer 404 includes a first set of bond pads 504 generally orientedaround the periphery of the extracted die/modified die Location 512. Thefirst set of bond pads 504 provide attachment points for new bond wires240 between the extracted die 100 and the interposer 404.

In general, each of the first set of bond pads 504 is electricallyconnected to each of a second set of bond pads 508 via reroutingcircuitry within the interposer 404. However, it is not a requirementthat every such pad 504, 508 be thusly connected. The second set of bondpads 508 is generally oriented around the periphery of the interposer404. The second set of bond pads 508 provide attachment points for newbond wires 240 between the interposer 404 and package leads 424 anddownbonds of the new integrated circuit package base 408.

In most applications, the interposer 404 is designed so that the secondbond pads 508 are as close as possible to the package base bond pad 604or package lead 424 that each second bond pad 508 gets bonded to. Thismay require routing connections between some first bond pads 504 andsecond bond pads 508 across most of the interposer 404. To some extentthe routing length of such connection may be mitigated by orienting theextracted die/modified die location 512 clockwise or counterclockwise onthe interposer 404, and this must be independently evaluated for eachextracted die 100/modified die 212 and interposer 404 combination.

Referring now to FIG. 6A, an illustration depicting a top view of a newpackage base 408 before wire bonding in accordance with embodiments ofthe present invention is shown. The remapped extracted die 608 issecurely mounted in the cavity 416 of the new package base 408 with dieattach adhesive 412. The new package base 408 has a plurality of packagebase bond pads 604, which provide a conduction path to the package leads424 on the exterior of the new package base 408. One package lead 424 isprovided on the exterior of the new package base 408 for every packagebase bond pad 604. The new package base 408 has different pinassignments than the previous package base the extracted die 100 wasremoved from.

Referring now to FIG. 6B, an illustration depicting a top view of a newpackage base 408 after wire bonding in accordance with embodiments ofthe present invention is shown. FIG. 6B illustrates the same point inthe assembly process as shown in FIG. 4A. The new package base 408 isfully assembled, and is ready for a package lid 432 to be added or elseencapsulation as a molded packaged integrated circuit 440.

As shown in FIG. 6B, the new package base 408 has new bond wires 240added. New bond wires 240 connect original bond pads 104, 108 of theextracted die 100 or modified die 212 to the first bond pads 504(usually but not necessarily, closest to the extracted die 100 ormodified die 212) of the interposer 404. Other new bond wires 240connect the second bond pads 508 (usually but not necessarily, closestto the edge of the interposer 404) of the interposer 404 to package basebond pads 604.

It is possible that some original bond pads 104, 108 of the extracteddie 100/modified die 212 and Package base bond pads 604 will be noconnects. No connects will not have a new bond wire 240 or new ball bond236 attached. In FIG. 6B, there are two no connects 616 on the originalbond pads 104, 108 of the extracted die 100, and two no connects 612 onthe package base bond pads 604. However, there may practically be anynumber of no connects, including zero.

Referring now to FIG. 7A, a flowchart illustrating an assembly methodfor a packaged integrated circuit 440 in accordance with a firstembodiment of the present invention is shown. Flow begins at block 704.

At block 704, an extracted die 100 is removed from previous packagedintegrated circuit. The extracted die 100 will have at least oneoriginal ball bond 112 and one original bond wire 116. It is possiblethat some or all existing original bond wires 116 will be removed duringthe die extraction process. Flow proceeds to block 708.

At block 708, original bond wires 116 are removed from original ballbonds 112 of extracted die 100, if any original bond wires 116 are stillpresent. Flow proceeds to block 712.

At block 712, the extracted die 100 is bonded to the interposer 404 tocreate a remapped extracted die 608. Flow proceeds to block 716.

At block 716, die attach adhesive 412 is applied to the package basecavity 416. Flow proceeds to block 720.

At block 720, the remapped extracted die 608 is placed into the packagebase cavity 416 to secure the remapped extracted die 608 to the newpackage base 408. As an alternative to blocks 712-720, the interposer404 may first be bonded to the new package base 408, then the extracteddie 100 may be bonded to the interposer 404. Flow proceeds to blocks 724and 728.

At block 724, new bond wires 240 are provided between the extracted die100 and the first set of bond pads 504 of the interposer 404. If thereis an original ball bond 112 on an original bond pad 104 of theextracted die 100, a new ball bond 236 is bonded to the original ballbond 112 as shown in FIG. 3B. Flow proceeds to block 732.

At block 728, new bond wires 240 are provided between the second bondpads 508 of the interposer 404 and package leads 424 or downbonds, asrequired. It should be noted that steps 724 and 728 may be completed inany order, depending on what new bond wire 240 installation produces themost efficient and reliable process. Flow proceeds to block 732.

At block 732, the package lid 432 is sealed to the assembled packagebase 400, or alternatively, the non-hermetic packaged integrated circuit440 is encapsulated. Flow proceeds to block 736.

At block 736, the packaged integrated circuit 440 is electricallytested. Electrical testing includes continuity tests or functionaltests, or both. If the packaged integrated circuit 440 has passed theelectrical tests, and the package leads 424 are properly trimmed, thepackaged integrated circuit 440 is marked and is a complete new packagedintegrated circuit 440 ready for use. Flow ends at block 736.

Referring now to FIG. 7B, a flowchart illustrating an assembly methodfor a packaged integrated circuit 440 in accordance with a secondembodiment of the present invention is shown. Flow begins at block 750.

At block 750, an extracted die 100 is removed from previous packagedintegrated circuit. The extracted die 100 will have at least oneoriginal ball bond 112 and one original bond wire 116. It is possiblethat some or all existing original bond wires 116 will be removed duringthe die extraction process. Flow proceeds to block 754.

At block 754, original bond wires 116 and original ball bonds 112 areremoved from extracted die 100. Flow proceeds to block 758.

At block 758, the original bond pads 104, 108 are conditioned and/orreconditioned. Conditioning includes removing any impurities fromoriginal bond pads 104, 108 and reconditioning applies an ENEPIG surfacetreatment in order to prepare the original bond pads 104, 108 to acceptnew ball bonds 236 and new bond wires 240. Instead of reconditioning,the original bond pads 104, 108 may be cleaned and/or lapped with allmetallic and chemical residues removed. Flow proceeds to block 762.

At block 762, the extracted die 100 is bonded to the interposer 404 tocreate a remapped extracted die 608. Flow proceeds to block 766.

At block 766, die attach adhesive 412 is applied to the package basecavity 416. Flow proceeds to block 770.

At block 770, the remapped extracted die 608 is placed into the packagebase cavity 416 to secure the remapped extracted die 608 to the newpackage base 408. As an alternative to blocks 762-770, the interposer404 may first be bonded to the new package base 408, then the extracteddie 100 may be bonded to the interposer 404. Flow proceeds to blocks 774and 778.

At block 774, new bond wires 240 are provided between original bond pads104, 108, conditioned original bond pads, or reconditioned bond pads 232of the extracted die 100 and the first set of bond pads 504 of theinterposer 404. Flow proceeds to block 782.

At block 778, new bond wires 240 are provided between the second bondpads 508 of the interposer 404 and package leads 424 or downbonds, asrequired. It should be noted that steps 774 and 778 may be completed inany order, depending on what new bond wire 240 installation produces themost efficient and reliable process. Flow proceeds to block 782.

At block 782, the package lid 432 is sealed to the assembled packagebase 400, or alternatively, the non-hermetic packaged integrated circuit440 is encapsulated. Flow proceeds to block 786.

At block 786, the packaged integrated circuit 440 is electricallytested. Electrical testing includes continuity tests or functionaltests, or both. If the packaged integrated circuit 440 has passed theelectrical tests, and the package leads 424 are properly trimmed, thepackaged integrated circuit 440 is marked and is a complete new packagedintegrated circuit 440 ready for use. Flow ends at block 786.

Referring now to FIG. 8A, a flowchart illustrating an assembly methodfor a hermetic packaged integrated circuit 452 in accordance with athird embodiment of the present invention is shown. Flow begins at block804.

At block 804, an extracted die 100 is removed from previous packagedintegrated circuit. The extracted die 100 will have at least oneoriginal ball bond 112 and one original bond wire 116. It is possiblethat some or all existing original bond wires 116 will be removed duringthe die extraction process. Flow proceeds to block 808.

At block 808, original bond wires 116 are removed from original ballbonds 112 of extracted die 100, if any original bond wires 116 are stillpresent. Flow proceeds to block 812.

At block 812, the extracted die 100 is bonded to the interposer 404 tocreate a remapped extracted die 608. Flow proceeds to block 816.

At block 816, a low halide content die attach adhesive 412 is applied tothe package base cavity 416. Flow proceeds to block 820.

At block 820, the remapped extracted die 608 is placed into the packagebase cavity 416 to secure the remapped extracted die 608 to the newpackage base 408. As an alternative to blocks 812-820, the interposer404 may first be bonded to the new package base 408, then the extracteddie 100 may be bonded to the interposer 404. Flow proceeds to blocks 824and 828.

At block 824, new bond wires 240 are provided between the extracted die100 and the first set of bond pads 504 of the interposer 404. If thereis an original ball bond 112 on an original bond pad 104 of theextracted die 100, a new ball bond 236 is bonded to the original ballbond 112 as shown in FIG. 3B. Flow proceeds to block 832.

At block 828, new bond wires 240 are provided between the second bondpads 508 of the interposer 404 and package leads 424 or downbonds, asrequired. It should be noted that steps 724 and 728 may be completed inany order, depending on what new bond wire 240 installation produces themost efficient and reliable process. Flow proceeds to block 832.

At block 832, the assembled hermetic package base 400 is first vacuumbaked. The assembled hermetic package base 400 includes the hermetic newpackage base 408, package leads 424, remapped extracted die 608, the dieattach adhesive 412, and new bond wires 240. The process of first vacuumbaking is illustrated in FIG. 11 of application Ser. No. 13/623,603.Flow proceeds to block 836.

At block 836, the assembled hermetic package base 400 is removed fromthe vacuum baking apparatus and the hermetic package lid 432 is placedon the assembled hermetic package base 400. The hermetic package lid 432is placed in proper orientation such that the combination of thehermetic package lid 432 and the assembled hermetic package base 400 ishermetically sealed following block 840. A moisture getter 444 may beapplied to the interior of the hermetic package lid 432. In a preferredembodiment, the moisture getter 444 is uniformly applied with athickness of three or more microns to the interior surface of thehermetic package lid 432 using a deposition process. Flow proceeds toblock 840.

At block 840, the assembled hermetic package base 400 and hermeticpackage lid 432 are placed into the vacuum baking apparatus and secondvacuum baked. Unlike block 832, where only the assembled hermeticpackage base 400 is first vacuum baked, block 840 requires the hermeticpackage lid 432 to be placed on the assembled hermetic package base 400prior to initiating the second vacuum bake process. The second vacuumbake process is illustrated in FIG. 12 of application Ser. No.13/623,603. Flow proceeds to block 844.

At block 844, a vacuum pump in the vacuum baking apparatus is turnedoff. Turning the vacuum pump off prevents gases from being evacuatedfrom the vacuum baking apparatus, and is required in order for noble gas448 injected in block 848 to remain in the packaged hermetic integratedcircuit 452 after the hermetic package lid 432 is sealed to theassembled hermetic package base 400. Flow proceeds to block 848.

At block 848, a noble gas 448 is injected into the packaged hermeticintegrated circuit 452, while the packaged hermetic integrated circuit452 is in the vacuum baking apparatus, and immediately following thesecond vacuum bake process. In a preferred embodiment, the noble gas 448is Argon, and the noble gas 448 is injected into the cavity 416 to apressure of between 0.1 to 2 Atmospheres (ATM), preferably 1 ATM, at atemperature between 200° C. and 275° C., preferably 255° C. Flowproceeds to block 852.

At block 852, the packaged hermetic integrated circuit 452 ishermetically and/or electrically tested. Hermetic testing is generallyperformed according to MIL-STD-883J. Electrical testing includes eithercontinuity tests or functional tests, or both. If the packaged hermeticintegrated circuit 452 has passed the hermeticity and electrical testsand the package leads 424 are properly trimmed to the appropriatelength, the packaged hermetic integrated circuit 452 is marked and is acomplete hermetic integrated circuit 452 ready for use. Flow ends atblock 852.

Referring now to FIG. 8B, a flowchart illustrating an assembly methodfor a hermetic packaged integrated circuit 452 in accordance with afourth embodiment of the present invention is shown. Flow begins atblock 804.

At block 856, an extracted die 100 is removed from previous packagedintegrated circuit. The extracted die 100 will have at least oneoriginal ball bond 112 and one original bond wire 116. It is possiblethat some or all existing original bond wires 115 will be removed duringthe die extraction process. Flow proceeds to block 860.

At block 860, original bond wires 116 are removed from original ballbonds 112 of extracted die 100. Flow proceeds to block 864.

At block 864, the original bond pads 104, 108 are conditioned and/orreconditioned. Conditioning includes removing any impurities fromoriginal bond pads 104, 108 and reconditioning applies an ENEPIG surfacetreatment in order to prepare the original bond pads 104, 108 to acceptnew ball bonds 236 and new bond wires 240. Instead of reconditioning,the original bond pads 104, 108 may be cleaned and/or lapped with allmetallic and chemical residues removed. Flow proceeds to block 868.

At block 868, the extracted die 100 is bonded to the interposer 404 tocreate a remapped extracted die 608. Flow proceeds to block 872.

At block 872, a low-halide content die attach adhesive 412 is applied tothe package base cavity 416. Flow proceeds to block 876.

At block 876, the remapped extracted die 608 is placed into the packagebase cavity 416 to secure the remapped extracted die 608 to the newpackage base 408. As an alternative to blocks 868-876, the interposer404 may first be bonded to the new package base 408, then the extracteddie 100 may be bonded to the interposer 404. Flow proceeds to blocks 880and 884.

At block 880, new bond wires 240 are provided between original bond pads104, 108, conditioned original bond pads, or reconditioned bond pads 232of the extracted die 100 and the first set of bond pads 504 of theinterposer 404. Flow proceeds to block 886.

At block 884, new bond wires 240 are provided between the second bondpads 508 of the interposer 404 and package leads 424 or downbonds, asrequired. It should be noted that steps 880 and 884 may be completed inany order, depending on what new bond wire 240 installation produces themost efficient and reliable process. Flow proceeds to block 886.

At block 886, the assembled hermetic package base 400 is first vacuumbaked. The assembled hermetic package base 400 includes the hermetic newpackage base 408, package leads 424, remapped extracted die 608, the dieattach adhesive 412, and new bond wires 240. The process of first vacuumbaking is illustrated in FIG. 11 of application Ser. No. 13/623,603.Flow proceeds to block 888.

At block 888, the assembled hermetic package base 400 is removed fromthe vacuum baking apparatus and the hermetic package lid 432 is placedon the assembled hermetic package base 400. The hermetic package lid 432is placed in proper orientation such that the combination of thehermetic package lid 432 and the assembled hermetic package base 400 ishermetically sealed following block 840. In some embodiments, a moisturegetter 444 is applied to the interior of the hermetic package lid 432.In a preferred embodiment, the moisture getter 444 is uniformly appliedwith a thickness of three or more microns to the interior surface of thehermetic package lid 432 using a deposition process. Flow proceeds toblock 890.

At block 890, the assembled hermetic package base 400 and hermeticpackage lid 432 are placed into the vacuum baking apparatus and secondvacuum baked. Unlike block 832, where only the assembled hermeticpackage base 400 is first vacuum baked, block 840 requires the hermeticpackage lid 432 to be placed on the assembled hermetic package base 400prior to initiating the second vacuum bake process. The second vacuumbake process is illustrated in FIG. 12 of application Ser. No.13/623,603. Flow proceeds to block 892.

At block 892, a vacuum pump in the vacuum baking apparatus is turnedoff. Turning the vacuum pump off prevents gases from being evacuatedfrom the vacuum baking apparatus, and is required in order for noble gas448 injected in block 848 to remain in the packaged hermetic integratedcircuit 452 after the hermetic package lid 432 is sealed to theassembled hermetic package base 400. Flow proceeds to block 894.

At block 894, a noble gas 448 is injected into the packaged hermeticintegrated circuit 452, while the packaged hermetic integrated circuit452 is in the vacuum baking apparatus, and immediately following thesecond vacuum bake process. In a preferred embodiment, the noble gas 448is Argon, and the noble gas 448 is injected into the cavity 416 to apressure of between 0.1 to 2 Atmospheres (ATM), preferably 1 ATM, at atemperature between 200° C. and 275° C., preferably 255° C. Flowproceeds to block 896.

At block 896, the packaged hermetic integrated circuit 452 ishermetically and/or electrically tested. Hermetic testing is generallyperformed according to MIL-STD-883J. Electrical testing includes eithercontinuity tests or functional tests, or both. If the packaged hermeticintegrated circuit 452 has passed the hermeticity and electrical testsand the package leads 424 are properly trimmed to the appropriatelength, the packaged hermetic integrated circuit 452 is marked and is acomplete hermetic integrated circuit 452 ready for use. Flow ends atblock 896.

Finally, those skilled in the art should appreciate that they canreadily use the disclosed conception and specific embodiments as a basisfor designing or modifying other structures for carrying out the samepurposes of the present invention without departing from the spirit andscope of the invention as defined by the appended claims.

We claim:
 1. A remapped extracted die, comprising: an extracted dieremoved from a previous integrated circuit package, the extracted diecomprising a plurality of original bond pads having locations that donot correspond to desired pin assignments of a new package base; and aninterposer, bonded to the extracted die, comprising: first bond padsconfigured to receive new bond wires from the plurality of original bondpads; and second bond pads corresponding to desired pin assignments ofthe new package base, each individually electrically coupled to one ofthe first bond pads and configured to receive new bond wires frompackage leads or downbonds of the new package base.
 2. The remappedextracted die of claim 1, wherein locations that do not correspond todesired pin assignments of a new package base comprises bond padlocations for new bond wires that cross other new bond wires if theextracted die is bonded to the new package base without the interposer.3. The remapped extracted die of claim 1, wherein a pinout of theprevious integrated circuit package is different than a pinout of thenew package base.
 4. A packaged integrated circuit, comprising: anextracted die removed from a previous packaged integrated circuit; a newpackage base, comprising package leads; an interposer, bonded to theextracted die and the new package base, comprising first and second bondpads; new bond wires, provided between the extracted die and first bondpads and between the second bond pads and package leads or downbonds tothe new package base; a package lid sealed to the new package base. 5.The packaged integrated circuit of claim 4, wherein original bond wiresare not bonded to the extracted die.
 6. The packaged integrated circuitof claim 5, wherein the extracted die comprises conditioned originalbond pads, wherein conditioned original bond pads comprises no originalbond wires or original ball bonds on the original bond pads and notraces of residues or oxides are present on the original bond pads,wherein the conditioned original bond pads are ready to accept new bondwires and new ball bonds.
 7. The packaged integrated circuit of claim 6,wherein the extracted die comprises reconditioned bond pads, whereinreconditioned bond pads comprises layers of nickel, palladium, and goldcovering the conditioned original bond pads, wherein the reconditionedbond pads are ready to accept new bond wires and new ball bonds.
 8. Thepackaged integrated circuit of claim 7, wherein new bond wires areprovided between the extracted die and first bond pads comprises newbond wires are provided between the reconditioned bond pads and firstbond pads.
 9. The packaged integrated circuit of claim 4, wherein newbond wires are provided between the extracted die and first bond padscomprises new bond wires provided between existing ball bonds on theextracted die and the first bond pads.
 10. The packaged integratedcircuit of claim 9, wherein the existing ball bonds were on originalbond pads within the previous packaged integrated circuit.
 11. Thepackaged integrated circuit of claim 4, wherein the interposertranslates first bond pad locations into second bond pad locations,wherein the second bond pad locations allow new bond wires to not crossother new bond wires between the second bond pads and package leads anddownbonds of the new package base.
 12. A new packaged integratedcircuit, comprising: a new package base, comprising a cavity and packageleads; a remapped extracted die, secured within the cavity, comprising:an extracted die removed from a previous packaged integrated circuit;and an interposer, bonded to the extracted die and the new package base,comprising first bond pads electrically coupled to second bond pads; newbond wires, provided between the extracted die and first bond pads andbetween the second bond pads and the package leads or downbonds; apackage lid sealed to the new package base.
 13. The new packagedintegrated circuit of claim 12, wherein second bond pad locations areconfigured to allow new bond wires to not cross other new bond wiresbetween the second bond pads and package leads or downbonds of the newpackage base.
 14. The new packaged integrated circuit of claim 12, theextracted die comprising: original bond pads; and one or more originalball bonds, wherein no original bond wires are coupled to the one ormore original ball bonds prior to bonding the extracted die to theinterposer.
 15. The new packaged integrated circuit of claim 14, whereinnew bond wires are provided between the extracted die and first bondpads comprises new bond wires are provided between original ball bondson the extracted die and the first bond pads.
 16. The new packagedintegrated circuit of claim 14, wherein original bond wires and originalball bonds are not bonded to the extracted die.
 17. The new packagedintegrated circuit of claim 16, wherein the extracted die comprisesconditioned original bond pads, wherein conditioned original bond padscomprises no original bond wires or original ball bonds on the originalbond pads and no traces of residues or oxides are present on theoriginal bond pads, wherein the conditioned original bond pads are readyto accept new bond wires and new ball bonds.
 18. The new packagedintegrated circuit of claim 16, wherein the extracted die comprisesreconditioned bond pads, wherein reconditioned bond pads comprises aNickel layer covering the conditioned original bond pads, a Palladiumlayer covering the Nickel layer, and a Gold layer covering the Palladiumlayer, wherein the reconditioned bond pads are ready to accept new bondwires and new ball bonds.
 19. The new packaged integrated circuit ofclaim 18, wherein new bond wires are provided between the extracted dieand first bond pads comprises new bond wires are provided between thereconditioned bond pads and first bond pads.
 20. The new packagedintegrated circuit of claim 12 comprising: a new hermetic package base;a hermetic package lid; and at least one of: a low-halide die attachadhesive; an inert noble gas; and a moisture getter.